For example, newspapers are printed by offset rotary presses. This newspaper offset rotary press is made up of a plurality of paper feeders, a plurality of printing units, a turn-bar unit, and a folding unit. Accordingly, each paper feeder feeds a web to a printing unit to conduct printing on each web. Then, the traveling routes of a plurality of webs are changed in the turn-bar unit, and then the plurality of webs are overlapped in the predetermined order. After that, in the folding unit, the webs are folded transversely to be then laterally cut at predetermined lengths and folded laterally, thereby forming a signature which is then discharged as newspapers.
A printing unit in such a newspaper offset rotary press requires a printing plate for printing articles or advertisement, and the printing plate is wound around a printing plate cylinder to conduct the printing operation. For this reason, to replace articles or advertisement, the printing unit has to be stopped to replace the printing plate. Thus, this may lead to a reduction in productivity of printing newspapers or to waste sheets.
Furthermore, when a reader having her/his interest in a particular field reads a newspaper, the reader must check all the newspaper pages by herself/himself to know the detailed contents though the pages are roughly classified by the type of articles or advertisement.
Note that a newspaper offset rotary press disclosed in Patent Documents 1 and 2 below is provided with an inkjet printing unit in addition to a printing unit, so that newspapers can be continuously printed without stopping the printing press.